Mobile marine drilling apparatus and method of use



July 22, 1969 W.D.M K|NTOSH 3,456,4 7

MOBILE MARINE DRILLING APPARATUS AND METHOD OF USE Filed July 10, 1967 2Sheets-Sheet 1 FIG. I

FIG. 3

INVENTOR WILLIAM D. MucKlNTOSH BY M ZMM ATTORNEY Q y 1969 w. 0. MKINTOSH 3,456,447

MOBILE MARINE DRILLING APPARATUS AND METHOD OF USE Filed July 10, 1967 2Sheets-Sheet 2 FIG. 5B FIG. 5C

WILLIAM D. MucKlNTOSH ATTORNEYS l N VENTOR United States Patent3,456,447 MOBILE MARINE DRILLING APPARATUS AND METHOD OF USE William D.MacKintosh, Tulsa, Okla., assignor to Sinclair Research, Inc., New York,N.Y., a corporation of Delaware Filed July 10, 1967, Ser. No. 652,249Int. Cl. E02b 17/00 US. Cl. 6146.5 Claims ABSTRACT OF THE DISCLOSURE Amobile marine drilling apparatus including an independent mobile derricksupport which carries a drilling derrick including the supplementaryequipment therefor and an independent mobile marine auxiliary platformadapted to be brought around the derrick support, attached thereto andraised by the supplementary derrick equipment including the travelingblock. The auxiliary platform can be used to stabilize the derricksupport and to raise and lower the derrick support.

Marine platforms which are mobile and carry the means necessary toanchor at desired offshore locations for drilling of oil wells therefromare well-known at the present time. While of many and variedconstructions, marine platforms generally are supported in operativeposition by means of a plurality of cylindrical members or columnarstructures which are anchored on the sea bottom and rise verticallytherefrom to the platform. For example, US, Patent 3,093,972 discloses amobile marine platform and a frame adapted to be submerged with theplatform subsequently being raised by the use of the frame to a desiredelevation above the water surface. However, this type of portableplatform lacks stability, especially while being transferred, i.e.,floated from one location to another, since vertical positioning of theframe tends to substantially raise the center of gravity of the platformthereby making it unseaworthy.

The present invention overcomes the disadvantages of the priorconstruction by providing an offshore exploration and productionassembly including an independent mobile marine auxiliary floatingplatform and a derrick platform which has its own independent mobilemarine support and which carries a drilling derrick including thesupplementary equipment therefor such as the traveling block. Thederrick support is stabilized by legs appended thereto and spread outbeneath the waves, thus presenting a stable structure which can operatein and above several hundred feet of Water.-When desired, the floatingauxiliary platform is brought around the support for the derrickplatform and attached thereto and the traveling block on the drillingderrick is used to raise and lower the auxiliary platform with respectto the derrick support. Using the traveling block to raise or lower theauxiliary platform eliminates the usual additional mechanisms associatedwith raising or lowering working platforms above water and renders itpossible to use the auxiliary platform as a floating dock alongsidewhich boats may be tied to load or unload cargo or crews in high seas ina much safer and more convenient manner than has heretofore beenpossible under such circumstances. This is possible because there isonly one support for the auxiliary platform around which it may rock inthe waves. This would not be possible if there were the usual multiplesupports. By contilevering the auxiliary platform on the derricksupport, a minimum amount of support area is exposed to the wave forces.In further usuage, the auxiliary platform provides a means for easilyremoving the exploration appurtenances, and the derrick platform andsupport may be "ice left, if desired, to serve as a production stationfor the well, or wells, after they have been developed.

The offshore exploration and production apparatus of the presentinvention is further described with reference to attached drawings inwhich:

FIGURE 1 is a side elevational view of the assembly of the presentinvention in which the auxiliary platform is mounted in an elevatedposition above the water surface;

FIGURE 2 is a plan view of the assembly;

FIGURE 3 is a partial side view of FIGURE 2 showing in more detail therelationship between the auxiliary platform and the derrick supportwhich is in a raised position;

FIGURE 4 illustrates in detail a portion of the attachment of theauxiliary platform to the derrick support; and

FIGURES SA-C illustrate in combination with FIG- URE l the operation ofthe auxiliary platform and derrick support.

Referring now to FIGURES 1 and 2, the assembly of the present inventioncomprises a derrick 14, derrick support 16 and auxiliary platform 12.Derrick support 16 includes a vertical section 16' which in use extendsbelow the Water surface 24 and has legs 18 spreading therefrom to feet20 to support the assembly on the ocean bottom 22. Derrick 14 issupported on a derrick platform 10 which is movably supported on derricksupport 16, particularly section 16. The auxiliary platform 12 is ofgeneral U-shape including a slot 12 which fits around the derricksupport section 16' and is attachable thereto in raised position by pins(not shown) such as pins 15, see FIGURE 3. The auxiliary platform 12 isalso engagable with elements of the drilling rig associated with thederrick 14, including traveling block 26, by cables 28' and is adaptedto be raised and lowered with respect to derrick support 16 by travelingblock 26 and cables 28. Cables 28, also shown, are attached to theauxiliary platform 12 and the derrick support 16 for raising andlowering the support 16 with respect to the auxiliary platform 12 bymeans of the traveling block 26. Traveling blocks and the requiredmotive means therefor are well known to one skilled in the art and, ingeneral, are used to raise and lower equipment, e.g., drill pipesections, with respect to the derrick 14. Rubber tired rollers 30 asshown in FIG- URE 4 are preferably attached to auxiliary platform 12 sothat during raising and lowering, or floating of platform 12 it canroll, e.g. with the waves at the ocean surface 24 without damage toderrick support 16. Rollers 30 are preferably spring-mounted to take upany slack between platform 12 and support 16. When platform 12 is at thedesired level, pins 15 are inserted in derrick support 16 to supportplatform 12 and release the traveling block 26 for drilling operations.Derrick platform 10 is moveable with respect to derrick support 16 by,e.g., screws 32 which are operated by motor 34 to keep the drillingplatform level and in its original position during drilling operations.p

' Feet 20 which are used to support the assembly on bottom 22 are hollowbodies sufficiently heavy in construction to withstand the highpressures to which they are subject when exposed several hundred feetbeneath the water. Each of the feet is a pontoon and is preferablyprovided with a relief valve to prevent the possibility of dangerouslyhigh pressure building up within the confines thereof. The pontoon feet20 are used to float the derrick support 16 for relocation. When it isdesired to move the drilling rig, auxiliary platform 12 is lowered tothe water surface and water jets 21 in the bottom of the pontoons,operable from the platform, e.g., auxiliary platform 12, are actuated tobreak the suction grip which develops if the pontoons sink in thebottom. Pumps on the platforms 10 or 12 then restore partial buoyancy topontoons 20 so that they may be raised off the bottom by cables 28' andtraveling block 26, as shown in FIG. SC, to facilitate relocation of thedrilling rig.

In positioning the drilling rig for drilling operations, the derrickplatform It} and derrick support 16 together with auxiliary platform 12,are towed, e.g., by tugs, from the construction site or former drillinglocation to the new drilling location in the positions shown in eitherFIG- URE 5A or 5C, for example. When in the position of FIGURE 5A,auxiliary platform 12 and the towing tugs are then attached one to eachof the pontoon feet of the derrick platform support 16 at the drillinglocation by means of hoist cables, not shown, to act as stabilizers, asthe whole framework is sunk to the bottom in the design area. The slot12 in the auxiliary platform is then brought around the derrick support16 as shown in FIG- URE 5B. Cables 28' are then attached to theauxiliary platform, and to traveling block 26 while it is in a loweredposition. The auxiliary platform 12 is then raised by cables 28' andtraveling block 26. Since derrick support 16 rests on the ocean bottom22, raising of the traveling block raises platform 12 with respectthereto. Auxiliary platform 12 is secured as shown in FIGURE 1, e.g., bypins, to derrick support 16 at the desired level, to provide additionalworking area. Auxiliary platform 12 can be easily raised and lowered bycables 28', when desired, to surface 24 to provide a floating dock forloading or unloading of cargo or crews. After the well is drilled, tofloat the rig to a new location, the auxiliary platform is lowered tothe water by cables 28 and traveling block 26, and cables 28 areattached to the traveling block in its lowered position. Raising of thetraveling block now raises derrick support 16 and derrick 14 from thebottom, using auxiliary platform 12 as a stabilizer, see FIGURE 5C. Inthis position, since the auxiliary platform 12 is floating, it providesa support base and the derrick support 16 can be raised and lowered withrespect thereto. After the rig has been thus floated, it is transportedto the new location, the derrick support is lowered to the bottom bycables 28 using auxiliary platform 12 as a stabilizer and the auxiliaryplatform 12 is again raised by cables 28 and attached to derrick support16 in the drilling position, as described above.

It is claimed:

1. An assembly for arranging and supporting a working area over a bodyof water which consists essentially of derrick support means including avertical portion extending both above and below the surface of the waterand leg means for supporting the assembly on the bottom of said body ofwater, a derrick platform supported by and movable vertically withrespect to said derrick support means, means for moving said derrickplatform with respect to said derrick support means, means for securingsaid derrick platform to said vertical portion at selected positionsthereon, derrick means on said derrick support means including travelingblock means for raising and lowering equipment with respect to saidderrick means, a floatable auxiliary working platform having a recessedportion on one side separably attachable to said derrick support meansat said recess and movable vertically with respect to said verticalportion, means for securing said auxiliary platform to said verticalportion at selected positions thereon, and means including saidtraveling block means for raising and lowering said auxiliary workingplatform with respect to said derrick support means whereby saidauxiliary working platform and said derrick platform are separablymovable with respect to each other and to the surface of said body ofwater.

2. The structure of claim 1 wherein said means for raising and loweringthe auxiliary platform are cables attached to said traveling blockmeans.

3. The structure of claim 2 wherein said means for securing saidauxiliary platform to the vertical portion are pins.

4. The structure of claim 2 wherein the means for raising and loweringthe derrick platform is a motor and screw means.

5. The structure of claim 2 wherein roller means are attached to saidauxiliary platform to cushion its movement against said verticalsection.

6. A method for providing a work area over a body of water utilizing astructure as defined in claim 2 comprising submerging said derricksupport means until said legs rest on the bottom of said body of water,lowering the traveling 'block means to said derrick platform, attachingthe traveling block means to the cable for raising and lowering theauxiliary platform, raising the traveling block means until saidauxiliary platform is at one of said selected positions therefor, andsecuring said auxiliary platform to said vertical portion.

7. A system for establishing a drilling rig for operation in a body ofwater to explore the ground submerged by the water, comprising: aderrick support, a drilling derrick and an adjustable derrick platformsupported by the derrick support, said derrick support having at leastthree spread legs with pontoon feet constructed for surface travel on abody of water and adapted to be flooded and submerged to the bottom andincluding means for restoring buoyancy to the same, a buoyant auxiliaryplatform constructed to fit around the derrick support on three sidesand adapted to float apart from the derrick support while the latter isbottomed and to be brought around the derrick support, means for raisingthe auxiliary platform above the surface of the water including meansoperable from the derrick platform on the support so that the twoplatforms may be used together to carry out the exploration, and meansfor lowering the auxiliary platform to float on the water around thebody framework to act as a floating dock to load or unload crews orcargo, and means for raising the derrick support operable from thederrick platform so that the derrick support and auxiliary platform canbe floated to a new location in the same area, and means for loweringthe derrick support to the bottom whereby the auxiliary platform canagain be raised; and means for keeping the derrick platform level asdrilling progresses including means for raising and lowering the derrickplatform with respect to the derrick support.

8. A system as defined in claim 7 further including water jet means inthe bottom of the pontoon feet operable from the derrick platform tobreak the suction grip which develops if the pontoon feet sink in thebottom.

9. A system as defined in claim 7 including means for securing theauxiliary platform at the level of said derrick platform.

10. A system as defined in claim 7 wherein the drilling derrick includestraveling block means and said means for raising and lowering theauxiliary platform comprises cables attached to the auxiliary platformand the traveling block means.

References Cited UNITED STATES PATENTS 2,430,014 11/1947 Hansen 6146.53,201,945 8/1965 Sutton 6146.5 3,241,324 3/1966 Storm et a1 6146.5

JACOB SHAPIRO, Primary Examiner

